Since premiering as a once-a-week broadcast in 1992, "Dateline" has spread from its Tuesday night base across the NBC schedule to Mondays, Fridays and Sundays.

So too with newsmagazines in general. When "Public Eye With Bryant Gumbel" joins the CBS lineup Wednesday night, there will be 10 newsmagazines on the networks' weekly prime-time schedule, with others such as "Hard Copy," "Inside Edition" and "American Journal" in syndication on a daily basis.

What's fueling the growth is both audience interest and television economics. At $400,000 to $600,000 per hour, newsmagazines cost about half as much as a prime-time entertainment show. Thus they can get by on lower ratings and make ideal fodder to throw into tough time periods where drama or comedy entries have failed repeatedly. That's why "Dateline NBC" has a 7 p.m. Sunday berth opposite CBS' perennial powerhouse "60 Minutes," and why both CBS' "48 Hours" and ABC's new edition of "20/20" find themselves battling NBC ratings-champion "ER" on Thursdays at 10 p.m.

But the proliferation of newsmagazines and the need to compete against entertainment programs for viewer attention is changing the kind of stories that get covered, critics charge.

"The trend in network newsmagazines is toward more tabloid-style stories and fewer big-picture pieces," said Russ Ptacek, whose Kansas-based company, Video Information News, provides crews to newsmagazines and keeps a log of newsmagazine stories to which producers subscribe.

"It's getting harder to tell the difference between 'Inside Edition' and the network newsmagazines," Ptacek says. "All of the network shows did lots of stories on Princess Diana, Andrew Cunanan and Jon-Benet Ramsey. And there's more duplication of stories among non-celebrity stories, too."

The story of the beauty-pageant winner who accused the Sultan of Brunei of forcing her into sexual slavery also was a popular subject, done by "Dateline," "Extra," "Entertainment Tonight," "Hard Copy" and "American Journal," he said, with some shows doing the story several times.

But NBC News President Andrew Lack says that focusing on such high-profile stories obscures the many serious, award-winning reports the newsmagazines do.

"In the middle of the Princess Diana story, 'Dateline' did an hour with [correspondent] John Hockenberry about discrimination against people with disabilities," Lack said. "But that's not the kind of story our critics write about."

And while he believes newsmagazines have an obligation to do serious journalism, CBS newsman Bernard Goldberg says that viewers have some obligation to.

"The audience gets away with murder in this discussion," says Goldberg, who was a correspondent on "48 Hours" for many years and now has joined "Public Eye." "When we put the West Bank [in Israel] and South Africa on '48 Hours,' nobody watched. When we did spring break, we got the highest ratings in the history of '48 Hours.' "